Method and apparatus for the launching of revetment mats



. 4, 1945. G. VAN DER REST.

METHOD AND APPARATUS FOR LAUNCHING REVETMENT MATS Filed Jan. 14, 1944 2 Sheets-Sheet 1 Fig.3]

FiqJII \nvznlor'. Gerard van der Res? G. VAN DER REST 2,390,403

METHOD AND APPARATUS FOR LAUNCHING REVETMENT MATS Filed Jan 14, 1944 Z SheetS -Sheet 2 VaNes I Ballast Tanx FloafTanK BaIIasTTanK l2 X -u Y u- Z Fuxahon j forCabkzs I Fia. Y

\nvenTor'. Gerard van am? R251 Patented Dec. 4, 1945 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR THE LAUNCHING OF REVETMENT MATS Gerard van der Rest, Carmel-by-the-Sea, Calif. Application January 14, 1944, Serial No. 518,488

6 Claims.

This invention deals with the under water placa much special and expensive machinery.

It is the placing under water or launching of prefabricated mats with which this invention is expensive method for placing pre-fabricated revetment mats under water. It is another purpose to carry this out Without the designed boats or launches, all equipment with exception of a float drum described later being conventional. Still another purpose is to make possible by this invention the use of mats which require less heavy reinforcement and are thus much cheaper to build than fore. Further purposes are suitable sinkable float drum to the desired location of placing) with means for sinking and refioating it, and means for holding and discharging the mat at the proper moment.

a drum, moving the so loaded drum to the exact at least partially submerged location for placing the mat, and unwinding the mat by rolling the drum at least part way under water whereby the Figures III and IV show diagrammatically the method of unwrapping the drum onmore or less level under water l'loors.

Figure V is a schematic elevated view of a drum employed for laying the inats.

Figure VI is an elevated cross sectional view of the left hand end of a drum, showing the valve mechanism. I

Figure VII iS'a side view of the same drum and valve mechanism. 1

drum resting on the upper V to wrapping it on, showing a slot and needed to fasten the mat onto the drum.

Figure IX is a cross sectional side view of the slot shown in Figure VIII.

Figure X is an enlarged bottom view of the same slot.

Referring to Figure I, a. mat I manufactured on a suitable site 2, preferably close to the waters edge, is wrapped onto a drum 3 shown in position A. A cable 4 is strung from the foot of winch 5 around drum 3 floating on the water and back to the roll of winch 5. When operating winch 5 as by moving handle 6 in clockwise direction to draw up the cable 4, drum 3 is first pulled to the edge of the. water and then is slowly rolled up the embankment 2 over the mat l. Drum 3 is rolled to the upper edge of mat l or close to it (position 3'). The edge is clamped to the drum in a manner described later. This done, the drum is then allowed to slowly back down wrapping up the mat as it rolls.

Where the site for manufacturing the mat is of a more or less permanent character, additional equipment to facilitate the placing of the drum on the upper edge of the mat may be employed. Thus, for example, the drum may be loaded on two trucks travelling on rails along both sides of the mat. These trucks are pulled up the grade with winches and deposit the drum at the desired spot.

After the complete mat has thus been wrapped onto the roll, the end is fixed by means of spikes driven into it and through the underlying layers of mat, or else, if a greater degree of fixation is needed, by means of easily detachable bands or cables. This is necessary in order to prevent premature unwrapping of the mat in If the location for laying subsequent movements.

If spikes are used, it is desirable that they be pre-coated with asphalt.

The drum now loaded with the mat is moved into the water where it floats and is brought to the exact location where the mat is to be laid.

the mat is a shore embankment as shown in Figure II, the drum is 2 turned around so that the original farther end of the drum is now the near end. It is then rolled up the grade by means of cables and winches, as described in connection with Figure I, to a line where it is desired to anchor the upper end of the mat. At this point, as the case may require, are removed and valves which areprovided in the end plates of the drum, are opened. Then the drum is slowly allowed to roll back dOWn into the water. As soon as the upper end of the mat lies flat, it may be anchored to the ground by anchor I as shown in Figure II. If the slope is insufficient at any one point to allow the drum to roll of its own accord, it may be pulled from the waterside. As the drum enters the water, the open valves permit water to enter into (position 3"). The construction of the drum lS such (as will be described later) of water sufficient only to sink it while loaded with the mat, but to allow it to float without the added weight of the mat. As a result the drum sinks and continues to roll on as far :as the guide cables will "let-it. A

The un become lighter tion will again olling of the mat causes the drum to and on account of its construcfloat when most of the mat has mat is completely the drum causes it to tear loose from the mat. The mat settles to the bottom of the water, and the free floating drum rises and is recovered. If the drum fails to tear loose from its own buoyancy, pulling it withcables will help.

When employing the above scheme, it is usually necessary to employ two or more winches (preferably coupled so that they forcibly turn at the same speed) :for each rolling operation in order to prevent straight path. Any side turn of the drum while the '--mat is being wrapped or unwrapped may result in damage to the mat or uneven laying or both. This may cause a much shorter life of the revetment than should normally be expected. The maximum speed at which the drum may be rolled to wrap or unwrap the mat is in general quite low and is limited by the flexing properties of the 'mat and the diameter of the'drum. Flexibility of the mat in turn is a thickness, type of binder, aggregate, temperature, etc. So no hard and fast rule can be laid regarding the speed of wrapping. On the average, a 2-inch asphalt mat on .a 6 to 8-foot drum may be wrapped at the rate of about minutes per turn.

f the water is navigable a tug, or tug and 'barge maybe used to tow the drum to the location of sinking, to guide the sinking drum and to unwrap the sunk drum. If, however, the distance of transporting the drum through navigable waters is relatively long, the charged drum may "be carried at least part of the distance in a cradle between two barges.

In order to lay mats on relatively level bottoms of navigable waters, the methods depicted in Figures III and IV may be-em'ployed. In this situation, the drum charged with the mat is sunk f-rom ajtug- 8 or barge 9 at the location of laying after the spikes or other means of fixing the loose end of the 'mat have been removed. After reaching bottom, the drum is then slowly rolled withcables attached to the tug, thereby unwrap- 'ping :the mat.

In canals and small rivers which often have unwrapped, the

it, as a result of which it continues the spikes or bands,

produced in a relatively strong current, a cross cable may be strung from bank to bank, and the drum may be floated to the desired location by means of a block travelling on the cross cable, a second cable being attached to the travelling block extending downstream the necessary distance. The mat is then again unrolled with cables and winch as described ,for Figure II.

In laying mats in waters having a current in one direction, it is important to have the several mats overlap, the overlapping ends pointing downstream. So in lining a canal or river or the like-with mats, onelhas to begin downstream and work upward.

From the above description, it will be realized that in order to carry out the wrapping, un- Wrapping, floating, sinking and re-floating successively, it is necessary that the mat and the drum meet certain requirements.

Obviously, the mat :must have a :certain tensile strength-as well as flexibility. Mats having these properties are quite well known and have been the past. .In general they are made of asphalt concrete reinforced with wire nets, cables, fabrics, etc.

Inasmuch as the mat must be floated and sunk, the specific gravity of the composition is of some importance. In general, it has been found that specific gravity stays fairly close to about 2 normally ranging from about 1.5 to 2.5 or in extreme cases as high as 3.

While the mat must have some tensile strength, it is in general not necessary that it be heavily reinforced. Ordinary :chicken wire, fish netting, duck or even weaker materials are usually of sufficient strength. The reason why the heavy reinforcements can be dispensed with lies in the particular methodof launching which I have invented. .I-Ieretoior it was necessary to launch such mats over the side of a boat, for instance by the method described by Shearer in U. S. Patent 1,229,152,. Because of the enormous weight of the mat when laying it at relatively great depths, the strong steel cable reinforcements were required.

The sizes of the mats may vary between extremely wide limits. In general it is desirable to make them as large as can be handled in order to reduce the number of seams, seams being the most vulnerable places where destruction of the revetment may set in. Thus both the width and the length of each mat may be several hundred f-eet, although x is probably the most .useiulaverage size. The thickness may also vary, depending upon the conditions to which the mat may be exposed during its useful'life. Thicknesses of from about 1 to '3 inches are most practical and suit most applications.

In general, it is desirable to standardize the composition as well as size and thickness of mats to be-laid inany one job; ,or if different measurements or compositions are required, atle'ast reduce their number to .a minimum. This 'isbecause noone launching drum is entirely suitable to handle mats .of widely varying measures'and the necessity of having to use many different drums complicates the handling and raises the cost.

Eor further information on the manufacture of flexible mats of the type described herein, reference is had to U. vS. Patents 1,874,567; 1,991,196 and 2,047,197.

In order that the mat shall not stick toitself when wrapped .upon the drum, fit is sometimes necessary to sprinkle it with a dry powder; Talc,

at any time. drum alone to float, even when the two ballast to cause the drum to etc., may

In order to accommodate as large a mat as possible, it is therefore desirable that the drum alone be relatively light. On the other hand, it must be built sufliciently strong so or smaller drums may be used. Their length may while leaving at least one compartment empty for floating the drum after discharge of the mat.

The size of the empty compartment must be suffiweight of the empty drum.

Referring to Figure V, a suitable drum III (which is preferably, though not necessarily cylindrical as shown) is divided into three compartments, X, Y and Z by partitions or bulkheads I I. Compartments X and Y are ballast tanks which can be filled with Water by opening the valves l3 at both end plates [2 of the drum. Compartment Y is a float tank sealed so that no water can enter Its volume is sufiicient to cause the tanks are completely filled with water. On the other hand the ballast tanks must be large enough sink when charged with a revetment mat.

If desired, sealed compartments having a total volume equal to that of Y may be at other locations inside of the drum to take the place of compartment 'Y. However, they should be axially disposed so that the drum is free to rotate when in water, and moreover they must be distributed over the length of the cylinder in such a way that the drum tends to sink in a horizontal position and will not nose down on one side.

Valves l3 must be positioned so as to permit entry. of the water at the right moment. This can be achieved either by having a series of valves close to the periphery of the end plates I2, so that regardless of which sector of the cylinder is submerged, water can flow in upon opening them; or else by providing a detachable weight or handle or the like which gives the drum'a definite top and bottom sector, and by further providing a top and bottom valve in each of the two end plates [2.

Since the valves must frequently be opened while the drum is afloat, it is desirable to provide a mechanism which can be operated by reaching from a boat. Such a suitable valve mechanism is shown in Figures VI and VII. A1- ternatively a jerk cord mechanism or the like may be employed to enable the opening of the the edge 29 of the support.

avalve stem I4, at the end of conical cam wheel l5. match a central cam wheel l6 whose plane of as shown is about of the 3 valves by an operator standing on a boat or on dry land some distance away.

Referring to Figures VI and VII, I 0 is the shell of the drum and I2 the end plates adjoining the ballast tank X, plate I2 carrying the valve mechanism. Six valves I3 are shown circularly arranged on end plate l2 near its periphery. They are of the plug valve type requiring only a quarter turn for opening and closing.

which there is a All six cam wheels I5 rotation is at a angle to the planes of rotation of cam wheels l5. I6 is attached to hand wheel l8 capable of rotating (within limits) around the central hub l1 mounted on the end late l2. Stops l9 restrict the movement of the hand wheel l8. When turning the hand wheel I8 within the limits permitted by stops l9, central cam It turns the cam wheels l5, which in turn open or close the valves I 2. Knob IS on top of hub I! serves as fixation point for cables which may be needed to tow the drum, or raise it should it fail to rise by itself. Groove 20 in the shell I0 near the edge of the drum serves as a guide for cables when wrapping or unwrapping the mat.

A detail not to be overlooked is the clamp for attaching the end of the mat to the drum when starting the wrapping onto the drum in accordof mat 2|. The mat lies on support 28 which is conveniently made of some firm material such as concrete, the end of the mat coinciding with The drum is held against stop 22 by cable 23. In the lower part of the drum (as positioned in Figure VIII) there is a peripheral slot 24, an enlarged bottom view of which is shown in Figure X and a cross-section' thereof along line AA is shown in Figure IX. This slot has a rectangular enlargement 25 at one or both ends, large enough to take the head of a suitable bolt. The slot 24 itself only accommodates the neck of the bolt. The inside of the entire slot is closed off byside walls 32 and covering 33. This is necessary to prevent water from entering the drum. While the length of the slot circumference, it may be longer or shorter. If desired, it may reach completely around'the drum.

A Z.-shaped clamp 26 is used to attach the end of the mat II to the drum, In order to put this pushed over the end of the mat and is tightened by tightening the nut.

In order to hold the mat along the entire length of the drum, it is of course necessary to provide more than a single peripheral slot 24. In general, it is desirable to have slots at least about every 4 to 8 feet along the entire length of the drum. The clamp 26 ma consist of a single piece extending the length of the drum; or it may be of several pieces, each piece preferably covering at least two slots.

In order to facilitate the pushing of the clamp over the end of the mat, it may be desirable to provide a shim under the end of the mat at edge 29, which shim is removed just before inserting 4- theclamp. Or else the-end of; the mat may hang a short distance over' the edgens The clamp thus holds the mat attached in a fixed position and unless the clamp is put on loosely or loosened, the mat is held; rat-her This might result. some difticulty in disengaging the drum from the mat alter the latter has been. unwrapped. To make sure that the mat will slipoff at the right moment, it is desirable that the reinforcement in the mat shall not extend to the very end. which is held in the clamp, butbe just slightly short of it as shown in Figure VII, 30' being the reinforcement in mat 2!. The end, it not reintorced, has very little tensile strength; and should the mat tail to slip out of the clamp whenv needed, it will merely tear oil, thereby permitting the mat to properly lie and release the drum. A cut or notch M in the mat will further facilitate the tearing off.

It may b'egldesirable to cut. openings into the mat at regular intervals which,'if properly placed so as to coincide with the clamp when wrapping up the'mat, may serve as windows through which the clamp may be loosened before the drum is launched. If this is done, the end of the mat will simply slip out when unwrapped. Openings in the mat are frequently necessary anyway, to allow water to escape that may have found its way under the mat. A convenient size for windows is abouti" x 4".

If desired, provision may further be made to introduce air into the drum should it for some reason refuse to re-float as described.v This. however would require the attachment of air hose through openings axially located in the two end plates [2, as well as a mechanism for closing the cient to sin-l: it, rolling "and lay the mat asoordoa it while charged with at least a substantial portion of said mat but to allow the uncharged drum to float, rolling the sunk drum on said location tounwrap and lay the mat, and disengaging the from the unwrappedmat whereby the drum is re-floated. V

3. The method of laying a prefabricated flexible. revetment mat in an at least partially submerged. location comprising wrapping said mat onto a float drum, moving the drum so charged into the water to float it, moving the floating drum to asubmerged edge of said location-causing water to enter the drum in an amount sumthe sunk drum to unwrap on. said location and disengaging the drum from the unwrapped mat.

A method bio revetment mat in a submerged location ,comprising wrapping said mat onto a float drum. moving the drum so charged into float it, moving the floating drum. to the desired position over said location, causing water to entop valve of; valves l3 while the drum is under water.

While in the preceding paragraphs I have described various. mechanical details of the appa-' ratus which is needed for carrying out my invention, it is understoodthat equivalents obvious to those skilled in the art may be employed,

I claim as my invention:

1. Method .for laying a pro-fabricated flexible revetment mat in a submerged location comprising wrapping said mat onto a float drum, moving the drum so charged into the water to float it, towing it to said location, causing water to enter the drum in an amount sufficientto sink it and to be deposited in said location, rolling the sunk drum on the location: to unwrap and lay the mat, disengaging the drum from the unwrapped mat floating: the disengaged drum.

2. Method for laying a pro-fabricated flexible revetment mat in a submerged location comprising wrapping said mat onto afloat drum, moving the drum so charged into the water to float it, towing it to said location, causing water to enter the drum in an amount'suflicient only to "sink to ter' the drum in an amount sufiicient to sink it onto said location, rolling the sunk drum to unwrap and layjthe' mat on said submerged location and disengaging the drum from the unwrapped mat.

5. A method for laying a flexible revetment mat in an at least partially submerged location, comprising manufacturing said mat on a flat sloping site above the water, placing a float drum.

on the upper end of said mat, the axis of said drum being substantially parallel to said upper end, attaching said end to said drum, slowly rolling the drum downward to wrap the mat onto the drum, moving the drum so charged into the water to float it, moving the floating drum to the desired position, causing water to enter the drum inan amount sufficient to sink it onto said location, rolling the sunk drum to unwrap and lay the mat on said location, and disengaging the drum from the unwrapped mat,

6. A method for laying a flexible revetment mat in an at least partially submerged location comprising manufacturing. said mat on a flat sloping site above the water, placing a float drum on the upper end of said mat, the axis of said drum being substantially parallel to said upper end, attaching said end to said drum, slowly rolling the drum downward to onto the drum, securing the remaining loose end of the mat to the dru charged into the water to float it, movingthe floating drum to the desiredposition, causing water to enter the drum in an amount sufficient to sink it onto said location, rolling. the sunk drum to unwrap and lay the mat on said location, and disengaging the drum from the unwrapped mat.

GERARD van DER. REST.

for laying a prefabricated 'flexi the water to wrap the mat a in, moving the drumso V 

